In the 1960s, Yugoslavia experimented with new bullet designs to produce a round with a superior wounding profile, speed, and accuracy to the original, Soviet M43 ammo. The resulting M67 ammo used a projectile that is shorter and flatter-based than the older M43, mainly due to the removal of the M43's mild steel insert. The removal of the insert has the wonderful side-effect of shifting the projectile's center of gravity rearward, thus allowing the projectile to destabilize and begin to yaw nearly 6.7" sooner in tissue. This yawing effect causes a pair of large stretch cavities at a depth likely to cause more effective wound trauma. (The most-likely wounding potential of M67 is limited to the typical small permanent wound channel the bullet itself makes, especially when the bullet does not tumble.)